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Date:   Tue, 21 Apr 2020 09:57:32 -0400
From:   Dan Schatzberg <schatzberg.dan@gmail.com>
To:     Hillf Danton <hdanton@sina.com>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 4/4] loop: Charge i/o to mem and blk cg
Message-ID: <20200421135732.GB9623@dschatzberg-fedora-PC0Y6AEN>
References: <20200420223936.6773-1-schatzberg.dan@gmail.com>
 <20200421033337.13208-1-hdanton@sina.com>
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On Tue, Apr 21, 2020 at 11:33:37AM +0800, Hillf Danton wrote:
> 
> On Mon, 20 Apr 2020 18:39:32 -0400 Dan Schatzberg wrote:
> > 
> > @@ -964,13 +960,16 @@ static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd)
> >  	worker = kzalloc(sizeof(struct loop_worker), GFP_NOWAIT | __GFP_NOWARN);
> >  	/*
> >  	 * In the event we cannot allocate a worker, just queue on the
> > -	 * rootcg worker
> > +	 * rootcg worker and issue the I/O as the rootcg
> >  	 */
> > -	if (!worker)
> > +	if (!worker) {
> > +		cmd->blkcg_css = NULL;
> > +		cmd->memcg_css = NULL;
> 
> Dunno if 	css_put(cmd->memcg_css);

Good catch. Need to drop the reference here.